Bone marrow procedures are commonly performed to diagnose various conditions that affect the different types of blood cells, to diagnose certain cancers to determine the extent of the cancer, and to obtain marrow for transplantation and/or graft preparation. The most frequent site for obtaining bone marrow is through the pelvic bone, known as the ilium. A portion of this bone is readily accessible in most people from the lower back and is usually marked by shallow dimples on either side of the spine. Other aspiration sites include the front of the pelvic bone near the groin and the sternum (chest).
A bone marrow aspiration procedure typically involves passing a bone marrow aspiration needle through the skin and soft tissue and into the bony cortex where the needle enters the spongy bone containing the bone marrow. The needle must be passed into the spongy bone at a sufficient depth before aspiration can be attempted. Once the needle is positioned in the spongy bone, a syringe or other fluid-withdrawing device is attached to the proximal end of the aspirator device and is used to collect the bone marrow. The needle can be repositioned several times to ensure that an adequate amount and/or sufficient sample is retrieved. The bone marrow is then prepared for examination, testing, or further use.
Various needle assemblies are available for aspirating bone marrow. These assemblies typically include a handle with a cannula extending distally from the handle. The handle is used by the physician to apply force to the cannula as the cannula is punctured through tissue and bone. Such needles also typically include a stylet or trocar with a sharpened distal tip which is inserted through the cannula and is used to initially puncture the bone. The stylet or trocar also serves to occlude the cannula while it is penetrating tissue prior to reaching the bone so that the marrow sample subsequently taken is free from unwanted tissue. Once the distal end of the device is positioned within the spongy bone, the stylet or trocar is removed and the syringe can then be connected to the cannula to withdraw bone marrow therethrough.
U.K. Patent No. 2,130,890 of Downs Surgical PLC discloses, for example, an aspiration needle having a transverse-bar, finger-grip handle, and a hollow needle extending distally therefrom. The hollow needle includes several perforations positioned around the distal end for drawing bone marrow therethrough. A stylet is removably positioned through the needle for penetrating the device into bone.
U.S. Pat. No. 4,969,870 of Kramer et al. discloses another aspiration apparatus which is particularly effective to indicate the depth of penetration. The device includes a base for placement against a patient's skin, and an elongated aspiration tube extending through a bore formed in the base. The aspiration tube includes a threaded lower end adapted to penetrate skin.
While these devices can be effective, they can often be difficult to maneuver due to the complexity of the device, as well as the number of parts. One disadvantage of current designs is the necessity to use one hand to do something other than manipulate the marrow retrieval device. The devices typically require a two-handed approach to insert the needle, and further require the additional step of removing the stylet once the needle is positioned, and connecting the syringe to the device. Other disadvantages of current designs include the need to frequently apply extensive rotary motion to the device. The handle must be designed to enable the physician to grasp and manipulate the device, and to apply a sufficient force to the device to puncture the tissue and bone. The shape of the stylet or trocar tip on current devices, however, can make penetrating through bone difficult. The ease of use of a bone marrow biopsy device will minimize the level of trauma visited upon the patient.
Accordingly, there is a need for an improved, user-friendly bone marrow aspiration device.